Router thicknessing sled

I needed to remove a lot of wood from a very badly cupped slab. So I decided it was time to finally cross “router planing sled” off my list of “gotta build me one of those.” Nothing too exciting about the sled itself, just a couple of pieces of angle iron screwed to some small pieces of scrap wood. A piece of plywood screwed in as a base plate to the router.

The unique part comes from the adjustable height sides. I went with simple, and completely adjustable. The side rails are made of 2”x12” with a pattern of 3/8” holes drilled so that I can use 6” long 3/8” diameter bolts with the threads cut off as pins to set the height. The pins support the side rails at the right height above the surface of my bench, then I just use clamps to hold them to the sides of the bench. With this setup I can go as high as 8.5” and down to less than a 1/2”. It can be fine tuned with shims between the bolt/pins and bench surface. Also allows for thicknessing a board with a tapered thickness (an upcoming project need).

I used a 1/2” straight bit in the the router. A surface planing / bottom cleaning bit might be more efficient, but I didn’t have one available. I was not worried about the final finish as I would do final dressing with handplanes and scraper A few extra details: Easy Router Planer

Nice idea. Adjusting the height of the side rails is a neat idea vs adjusting the depth of the bit. The only improvement might be to place insert nuts in the sides of your bench and use bolts to hold the rails. Then you won’t have to fiddle with long clamps under the bench while holding the rails in place.

This was more one of those creative spurts caused by not wanting to go buy more stuff ;)

Thanks @builtinbkn I still used the router to adjust depth of each pass, Then I adjust the rails to lower when the router is at its lowest limit. I like your suggestion about the insert nuts, but then I would lose the ability to shim up one end or one side to make fine adjustments for a level plane. Also since the distance between the nuts would be fixed, I wouldn’t be able to set one end to a different height than the other. I want to be able to create slabs that have a tapered thickness… like 2” on one end tapering to 1” on the other end.

Hmmm? I thought you used those holes in the rails to set the level using those metal rods (can’t tell exactly what they are). You could still do the same except with bolts passing the the holes. Ah maybe I’m looking at it wrong :)

This was more one of those creative spurts caused by not wanting to go buy more stuff ;)

Thanks @builtinbkn I still used the router to adjust depth of each pass, Then I adjust the rails to lower when the router is at its lowest limit. I like your suggestion about the insert nuts, but then I would lose the ability to shim up one end or one side to make fine adjustments for a level plane. Also since the distance between the nuts would be fixed, I wouldn t be able to set one end to a different height than the other. I want to be able to create slabs that have a tapered thickness… like 2” on one end tapering to 1” on the other end.

@bulltinbkn I do use them to set the rough depth. It goes sort of like this:

1. I start with side rails set to whatever the max starting height is. 2 Using the router adjust I drop the bit until it just touches the highest point of the workpiece. 3. drop it 1/4” 4. start routing back and forth. 5. when that level is fully taken down, repeat step 3 and 46. when the router won’t go any lower, I pull out the pins from the sideboards and move them down an inch. (that’s about the max depth of the bit I am using) 7. Repeat step 2 and continue8. When I am ready for my last 1/4” or 1/8” pass (in other words the bulk removal is done), then I take careful measurements of the height of the wooden side rails and adjust with shims under the pins to make them completely planar with the bench top.9. When the last pass is done, then I take the rails off and use a hand plane and or cardscraper to finish the surface of the wood.

If you look closely at the last photo you can see where the 4 bolt/pins are resting on the bench top. Unfortunately, none of them have shims under them at the time so you can’t see that.

If the pins went into holes in the bench or into holes with t-nuts, I wouldn’t be able to do fine adjustments with shims. I also would not be able to intentionally set one end higher than the other because the pins would not be the same distance apart that they are when they are set to be level.